JPH117622A - Substrate for magnetic record medium, magnetic record medium and production of magnetic record medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy both of magnetic recording characteristics and enough reliability of sliding resistance by sputtering a material essentially comprising intermetallic compd. to form fine projections essentially comprising the intermetallic compd. on the surface of a substrate and then subjecting the surface to laser processing to form annular projections only in a CSS zone. SOLUTION: After a base alloy layer 102 of Co, Cr, Ta is formed on a disk- type glass substrate 101, fine projections 103 comprising an intermetallic compd. of Al and Co are formed on the base alloy layer 102 by sputtering a target comprising Al-14.6 at.% Co. Then the CSS zone of the substrate 101 where fine projections 103 are formed is processed with laser beams to form discrete annular projections 105. Further, an alloy layer 106, a magnetic recording layer 107, and a protective film layer 108 are formed thereon. Thereby, the obtd. medium hardly causes sticking of a head and has excellent sliding resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic disk for providing a magnetic disk device having good sliding reliability, and a magnetic recording medium used for such a magnetic recording medium. The present invention relates to a method for manufacturing a substrate and a magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording media, higher recording densities of information have been progressing along with miniaturization and large capacity of magnetic disk drives. To increase the recording density, it is important to reduce the distance between the magnetic recording medium and the head. However, if both the magnetic recording medium and the head have smooth surfaces, contact start / stop (CSS )
Occasionally, the location where they abut will have high stiction, and in the presence of lubricant, sticking can occur. For this reason, the flying height of the head in the area (data zone) for recording information on the magnetic recording medium is reduced as much as possible, as well as the low adhesiveness in the area (CSS zone) where the head contacts the magnetic recording medium during CSS. In order to make it wider, it has been proposed that the CSS zone be given a higher discrete protrusion shape than the data zone. As an example of this, as described in JP-A-3-272018, a surface having a protrusion with a roughness (Rp) of 2.54 nm or less is formed by mechanically processing the entire surface of a substrate of a magnetic recording medium. After that, there is a method of forming annular projections by laser processing only in the CSS zone. Also, Japanese Patent Application Laid-Open No. 8-147662 proposes a configuration in which a metal capable of forming carbide is sputtered on the entire surface of a carbon substrate to form projections with good adhesion.

[0003]

According to the method described in Japanese Patent Application Laid-Open No. 3-272018, a magnetic recording medium having good CSS characteristics can be provided. However, in the data zone, the surface of the substrate has a roughness of 2.54 nm or less. In the case where the head has a protrusion and an unexpected contact between the head and the magnetic recording medium occurs during data recording / reproduction, the anti-adhesion property is not clear. Further, it is difficult to perform efficient laser processing on a glass substrate. Further, JP-A-8-147662 states that both magnetic recording characteristics and sliding reliability can be achieved, but it is clear whether sufficient sliding reliability can be obtained with a substrate other than a carbon substrate. Not.

The present invention has been made in view of these problems of the prior art.

[0005]

In order to achieve the object of the present invention, a fine metal is deposited on the surface of a magnetic recording medium by sputtering the substrate with a material mainly containing an intermetallic compound as a target. After forming the protrusion mainly containing the inter-compound, an annular protrusion is formed only in the CSS zone by laser processing. On the glass substrate, a non-magnetic metal thin film is formed by sputtering, and then a projection mainly composed of an intermetallic compound is formed. Further, a magnetic recording layer, a protective layer, and a lubricating layer are sequentially formed on the substrate on which the protrusion mainly composed of an intermetallic compound and the annular protrusion formed by laser processing are formed. According to this method, a magnetic recording medium that simultaneously satisfies magnetic recording characteristics and sliding reliability can be easily configured. These projections can also be formed after the formation of the magnetic recording layer. Sputtering was performed on a substrate whose area other than the CSS zone was masked using a material mainly composed of an intermetallic compound as a target, thereby forming fine projections mainly composed of an intermetallic compound mainly in the CSS zone. The object of the present invention can be achieved by using a substrate.

First, a method of forming an annular projection on a glass substrate by laser processing when a glass substrate is used as the substrate will be described. The material of the glass substrate is
It is optically transparent to light having a wavelength in the range of 400 to 2000 nm, and hardly absorbs laser energy. For this reason, attempts have heretofore been made to use a laser having a wavelength that can be absorbed by glass, such as a carbon dioxide laser, or to use a special glass material that efficiently absorbs a specific wavelength for a substrate. In the present invention, a method of forming a nonmagnetic metal thin film on a soda lime glass substrate generally used for a substrate for a magnetic recording medium, and efficiently forming annular protrusions by a relatively low output laser I will provide a.
According to this method, an annular projection can be formed on a general glass substrate using a solid-state laser that is easy to handle. When processing is performed by laser irradiation, the amount of processing depends on the amount of energy input to a minute portion irradiated with laser. The input energy amount is an amount obtained by subtracting the energy amount flowing out by heat conduction from the energy amount absorbed by the minute portion irradiated with the laser. It is known that soda lime glass generally shows a transmittance of 90% or more for light having a wavelength in the range of 400 to 2000 nm,
It is quite difficult to perform laser processing directly on a soda-lime glass substrate. On the other hand, even if the metal material is a thin film, its transmittance is substantially zero for the wavelength in the above range.
Also, the reflectance of metal materials for aluminum, silver, copper, etc. shows a high value for the wavelengths in the above range, but nickel, chromium or other alloys show relatively low reflectance. Energy can be easily absorbed. Further, once the material is evaporated or liquefied by laser irradiation on the surface, the laser is scattered and absorption becomes easier. The thermal conductivity of metal is, for example, about 100 W / (m
・ K), even stainless steel SUS304 with low thermal conductivity is 10
In contrast to W / (m · K) or more, glass is near 1 W / (m · K).

Therefore, by forming a thin film of a metal material that absorbs laser light of a desired wavelength on a substrate having a low thermal conductivity such as a glass substrate, the input energy can be increased, and the efficiency can be increased. Laser processing becomes possible.

It is to be noted that the object can also be achieved by forming a thin film of a substance having a low thermal conductivity such as silicon dioxide on a substrate having a low thermal conductivity such as a glass substrate and then forming a thin film of the metal material. it can.

If there is no limitation on the usable laser power, a substrate using a material such as an aluminum alloy may of course be used.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the present invention, the outline of the present invention will be described. First, a method for forming a projection mainly composed of an intermetallic compound on a substrate such as a glass substrate on which a thin film of a metal material which absorbs laser light having a desired wavelength is formed by sputtering will be described. First, in order for a projection to be formed, the force of attracting constituent atoms forming the projection must be greater than the force of diffusing to the substrate surface and flattening. Further, it is necessary that after the projections are formed, the constituent atoms do not substantially diffuse over a long distance and do not substantially react with the adjacent layers. From the above, it is preferable that the substance forming the protrusion is not a single element but a substance in which two or more kinds of element atoms are bonded to each other. In addition, since it is desirable that each constituent atom does not substantially react with an adjacent layer, highly reactive atoms such as alkali metals, alkaline earth metals, and halogen elements are excluded as these constituent atoms. Therefore, an intermetallic compound is suitable as the substance forming the protrusion. Here, the intermetallic compound is a substance having a certain composition ratio composed of two or more kinds of metal elements excluding an alkali metal and an alkaline earth metal, and generally has a crystal structure different from that of a single element. Since the use of an intermetallic compound does not require heating after the formation of the projections, it is desirable from the viewpoint of suppressing the diffusion of constituent atoms.

Next, a process of forming a projection mainly composed of an intermetallic compound will be described with reference to FIGS.
FIG. 1 is a part of an AB system equilibrium diagram having an intermetallic compound phase. FIGS. 2, 3, and 4 schematically show the process of forming the projections. In FIG. 1, the vertical axis is temperature, and the horizontal axis is
Shows the concentration of B atoms in the AB system. For example, at point C in FIG.
When the concentration of atoms is x1, it is energetically stable that the phase α and the phase θ exist at the ratio of b to a at the temperature T1. Therefore, if the composition is x1, the phase α and the phase θ are generated at a ratio of b to a by maintaining the temperature T1 for a long enough time to sufficiently cause diffusion at the temperature T1. The phase of only θ can be obtained.

Next, a process of forming a projection will be described with reference to FIGS. FIGS. 2, 3, and 4 schematically show the process of forming the projections, and the arrangement or number of atoms is not necessarily the same as in the actual example.

First, when a target having a composition of x1 shown in FIG. 1 is sputtered, A atoms and B atoms reach the substrate 1 and combine to form a crystal nucleus 2 of an intermetallic compound θ (FIG. 1). 2). A and B atoms are continuously supplied on the substrate 1. A atom 3 and B atom 4 continue to reach the place where the crystal nucleus 2 of the intermetallic compound does not exist on the substrate 1 with the same probability, but the atom that forms the intermetallic compound is a free atom Therefore, the driving force of diffusion works until the composition in the equilibrium state (absolute ratio of α and θ phases = b: a), and the crystal nucleus 2 of the intermetallic compound θ continues to grow ( (Fig. 3). The diffusion coefficient at the substrate surface is large enough to form an intermetallic compound even at a low temperature of 600 K or less. In general, the crystal nucleus 2 attempts to stabilize by minimizing the surface area and minimizing the interfacial energy. Therefore, the size of one crystal nucleus tends to be close to a hemisphere on the substrate 1. The reason why the size of a single element is increased is apparent from the fact that, for a similar shape, the surface area increases in proportion to the square of the radius, and the number of atoms increases in proportion to the cube of the radius.

The crystal nuclei 2 grow and become projections 21 made of an intermetallic compound. In the composition x1, an α phase exists in addition to the θ phase of the intermetallic compound in an equilibrium state after a sufficient time for diffusion. These atoms diffuse freely without being constrained because there is substantially no B atom to react,
Most of them are uniformly distributed on the outermost surface having a high diffusion coefficient (FIG. 4).

The above process is time dependent. For example, the diffusion rate increases as the substrate temperature increases, and the height of the protrusion 21 made of an intermetallic compound can be increased within a certain time. Further, the frequency of occurrence of the crystal nuclei 2 is affected by the material of the base formed on the substrate 1.

Therefore, the density of the projections 21 made of an intermetallic compound can be controlled to a desired range by appropriately selecting the base material. The material of the base may be any material as long as the composition and the temperature are well defined.

The target used in the present invention may be any system as long as it can generate an intermetallic compound as described above. However, since Al is easily diffused even at a low temperature, Al is selected as the A atom 3. Is preferred. In addition, the thermal stability of the intermetallic compound can be improved, the reactivity between the intermetallic compound and the films formed above and below the protrusions of the intermetallic compound can be reduced. Since it can be formed as a B atom 4, a high melting point metal element with a melting point of 1000 ° C or more (Co, Cr, Cu, Fe, Mn, Mo, Ni, Pd, Pt, V, W, etc.)
Is desirable. Further, it is preferable to select Al as the A atom 3 and an element selected from Cr, Co, Mo, V, and W as the B atom 4 from the viewpoint of the target manufacturing method, the price, and the like.

In the present invention, after a projection made of an intermetallic compound is formed on the substrate surface, an annular projection is formed only in the CSS zone by laser processing. By rotating the substrate at a speed corresponding to the frequency of the pulsed laser, annular projections are regularly arranged at regular intervals. In the case of using a glass substrate, laser processing can be performed later by forming a non-magnetic metal thin film as a base film on the substrate by sputtering before forming a projection made of an intermetallic compound. The protrusion made of an intermetallic compound formed on the surface of the substrate is processed together with a metal thin film as a base film during laser processing.

According to the present invention, it is possible to obtain a magnetic recording medium which is hard to stick to the head and has excellent sliding resistance, and can provide a magnetic disk drive having excellent sliding reliability.

As a substrate for a magnetic disk, a substrate made of an aluminum alloy and plated with nickel phosphorus is often used. However, since the heat capacity of the substrate is large,
There is a drawback that efficient laser processing is difficult. This problem is an important problem to be solved in connection with the densification of protrusions, which has recently become stronger. That is,
In order to improve the CSS proof strength while avoiding sticking, it tends to arrange more protrusions, but the energy required to form one protrusion is the same, so more protrusions are formed per unit time. For this purpose, a laser having a higher output is required. However, from the viewpoints of cost, ease of use, and the like, a method capable of processing with smaller laser power is desirable. For that purpose, it is necessary to keep the energy required to form one projection smaller than before. The present invention has been made in view of the above-described problems, and has been made in order to easily configure a magnetic disk having an annular protrusion formed with a smaller laser power on a metal substrate and having excellent sliding reliability.

In order to achieve the object of the present invention, an alloy film is laminated on a substrate on which an oxide film or a nitride film of silicon (hereinafter referred to as Si) is formed, and then the substrate is subjected to laser processing.
An annular protrusion is formed only in the CSS zone. In addition, CSS
In order to realize a stable floating above the data zone other than the zone, projections lower than the projections formed by the laser processing are formed on the entire surface of the substrate by sputtering a target containing an intermetallic compound. A magnetic recording layer, a protective layer, and a lubricating layer are sequentially formed on the substrate on which these protrusions are formed.
According to this method, a magnetic disk that simultaneously satisfies magnetic recording characteristics and sliding reliability can be easily configured. In this case, the order of the projection formation by the laser processing and the projection formation by the sputtering may be reversed. After forming the magnetic recording layer, one or both of the formation of protrusions by laser processing and the formation of protrusions by sputtering may be performed.

First, a method of forming an annular projection on a substrate by laser processing will be described. When processing is performed by laser irradiation, the amount of processing depends on the amount of energy input to the minute part irradiated with the laser. The input energy amount is an amount obtained by subtracting the energy amount flowing out by heat conduction from the energy amount absorbed by the minute portion irradiated with the laser. Even if the metal material is a thin film, the transmittance is substantially zero for the wavelength in the above range. Also, the reflectance of the metal material is high for aluminum, silver, copper and the like for the wavelengths in the above range, but nickel, chromium and other alloys are said to show a relatively low reflectance, and these The material can easily absorb the energy of the laser. Further, once the material is evaporated or liquefied by laser irradiation on the surface, the laser is scattered and absorption becomes easier. On the other hand, the thermal conductivity of metal is, for example, aluminum alloy A5083 is approximately 100 W / (m
4 is 10 W / (mK) or more, whereas glass is 1 W / (m
K) It is near. For this reason, after forming a thin film of a substance having a low thermal conductivity such as silicon dioxide on a substrate having a high thermal conductivity such as an aluminum alloy substrate, a thin film of a metal material that absorbs laser light of a desired wavelength is formed. Thus, the input energy amount can be increased, and efficient laser processing can be performed. By rotating the disk at a speed corresponding to the frequency of the pulsed laser, annular projections are regularly arranged at regular intervals.

Next, the process of forming fine projections by sputtering will be described with reference to FIGS. 1, 2, 3 and 4 as described above.

First, in order for a projection to be formed, the attractive force of the constituent atoms forming the projection must be greater than the force for diffusing to the substrate surface and flattening. Further, it is necessary that after the projections are formed, the constituent atoms do not substantially diffuse over a long distance and do not substantially react with the adjacent layers. From the above, it is preferable that the substance forming the protrusion is not a single element but a substance in which two or more kinds of element atoms are bonded to each other. In addition, since it is desirable that each constituent atom does not substantially react with an adjacent layer,
As the constituent atoms, highly reactive atoms such as alkali metals, alkaline earth metals, and halogen elements are excluded. From the above two points, an intermetallic compound is suitable for the substance forming the protrusion. Here, the intermetallic compound is a substance having a certain composition ratio composed of two or more kinds of metal elements excluding an alkali metal and an alkaline earth metal, and generally has a crystal structure different from that of a single element. The use of an intermetallic compound is desirable from the viewpoint of suppressing the diffusion of constituent atoms since heating is not required after the formation of the projections.

FIG. 1 is a part of an AB system equilibrium diagram having an intermetallic compound phase. FIGS. 2, 3, and 4 schematically show the process of forming the projections. In FIG. 1, the vertical axis represents temperature, and the horizontal axis represents the concentration of B atoms in the AB system. For example, at the point indicated by x in FIG. 1, when the concentration of B atoms is x1, the temperature T
1 indicates that the phase α and the phase θ are present in a ratio of b to a, respectively, in terms of energy stability. Therefore x1
If the composition is held for a long time to the extent that diffusion occurs sufficiently at the temperature T1, the phase α and the phase θ are generated in the ratio of b to a, respectively, and if the composition is x2, the phase of only θ is obtained at the temperature T1. be able to. Next, a process of forming the projection will be described with reference to FIGS. FIGS. 2, 3, and 4 schematically show the process of forming the projections, and the arrangement or number of atoms is not necessarily the same as in the actual example.

First, in FIG. 1, when a target having a composition of x1 is sputtered, atoms A and B reach the substrate and are bonded to each other to form a crystal nucleus of the intermetallic compound θ (FIG. 2).
A and B atoms are continuously supplied on the substrate. Each of the atoms A and B continues to reach the place where the crystal nucleus of the intermetallic compound does not exist on the substrate with the same probability, but the formation of the intermetallic compound is more energetic than the free atom. , The composition in the equilibrium state (absolute ratio of α, θ phase
= b: a), the driving force of diffusion works until the intermetallic compound θ
Crystal continues to grow (FIG. 3). A, B without A
Atoms are indicated by a hatched circle. (Note that the diffusion coefficient at the substrate surface is large enough to form the intermetallic compound even at a low temperature of 600 K or less.) Generally, the crystal nucleus attempts to stabilize by minimizing the surface area and minimizing the interfacial energy. Above, it is close to a hemisphere and one dimension tends to be large. The reason that one dimension becomes larger is that if it is similar, the surface area is proportional to the square of the radius,
This is evident from the fact that the number of atoms increases in proportion to the cube.

In the composition x1, an α phase exists in addition to the intermetallic compound θ phase in an equilibrium state after a sufficient time for diffusion. These atoms diffuse freely without being bound by the fact that there is substantially no atom B to react,
Most of them are uniformly distributed on the outermost surface having a high diffusion coefficient (FIG. 4).

This process is time dependent. For example, the higher the substrate temperature, the higher the diffusion speed, and the height of the protrusion can be increased within a certain time. The frequency of occurrence of crystal nuclei is affected by the material of the base. By appropriately selecting this, a desired projection density can be obtained. The material of the base may be any material as long as its composition and temperature are well defined.

The above-mentioned mechanism is not limited to a binary system, but is also applicable to a ternary system or more. The target used in the present invention may be any system as long as it can generate an intermetallic compound as described above, but Al is easily diffused even at a low temperature, so Al is used as the A atom, and the thermal stability of the intermetallic compound is increased. B, since it is possible to improve the reactivity and reduce the reactivity between the intermetallic compound and the film formed above and below the protrusion of the intermetallic compound, and to form finer protrusions of the intermetallic compound at a high density.
High melting point metal elements (Co, Cr, C
Intermetallic compounds containing u, Fe, Mn, Mo, Ni, Pd, Pt, V, W, etc.) are desirable. Further, it is preferable to select Al as the A atom and an element selected from Cr, Co, Mo, V, and W as the B atom from the viewpoint of the target manufacturing method, price, and the like.

According to the present invention, a laser processing on a metal substrate can be performed with a small laser power. As a result, a magnetic disk which is less likely to stick to the head and has excellent sliding resistance can be obtained with a simpler apparatus, and the sliding reliability can be improved. An excellent magnetic disk drive can be provided.

Next, an embodiment of the present invention will be described.

Embodiment 1 A magnetic recording medium according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is a sectional view showing a configuration in which a projection made of an intermetallic compound is formed on a substrate in the magnetic recording medium of this embodiment.

First, a disk-shaped glass substrate 101 having an outer diameter of 95 mm, an inner diameter of 25 mm, and a thickness of 0.8 mm and having a concentric hole in the center is heated by a lamp in a vacuum for degassing. The input power at this time is controlled so that the temperature becomes high enough not to deform the substrate 101. Typically, the temperature is set at 100 to 250 ° C. Thereafter, cobalt (hereinafter, referred to as Co), chromium (hereinafter, referred to as Cr), and tantalum (hereinafter, referred to as Ta)
) Is formed. The composition ratios of Cr and Ta are 30 atomic% and 8 atomic%, respectively.
The composition of 2 is substantially non-magnetic. The alloy layer 102
The four film thicknesses of 25, 50, 100 and 200 nm were prepared. The smaller the film thickness, the smaller the heat capacity of the entire film, and processing is performed with a small laser power. Further, as a material constituting the alloy layer 102, an alloy of Cr and silicon (denoted by Si), an alloy of Cr and titanium (denoted by Ti), Cr and vanadium (denoted by V)
, An alloy of nickel (referred to as Ni) and Ti, an alloy of Ni and Al, and a ternary alloy of Co, Cr and zirconium (referred to as Zr) were studied. This is because the physical properties such as the absorption efficiency from the laser and the thermal conductivity differ depending on each material. Process conditions that can be set in both the thin film formation process and the laser processing process often have restrictions from the manufacturing facility side, and it is advantageous to study various process parameters in actual manufacturing.

The alloy layer 102 on the substrate 101 has a function of forming projections by irradiation with a pulse laser. Alloy layer 10
The material used for 2 may be any other material as long as it has the functions and effects described above. In addition, although a glass substrate manufactured by Nikon Corporation is used for the substrate 101, any material may be used as long as it is nonmagnetic and has no problem in flatness and strength.

Thereafter, the substrate 101 is processed for a predetermined time in a processing chamber equipped with a helium introduction mechanism, and the substrate temperature is changed to Al and Co.
Is cooled to a predetermined temperature suitable for forming the projection 103 made of the intermetallic compound. This cooling step is performed on the substrate 10
This is unnecessary if the temperature of the substrate 101 has dropped to a predetermined temperature due to radiation, conduction, or the like during the transfer of 1 from the processing chamber to the processing chamber. Any gas may be used as long as it has a cooling effect. On the other hand, when the temperature is too low, heating is performed again to a predetermined temperature.

Subsequently, a projection 103 made of an intermetallic compound of Al and Co is formed on the alloy layer 102 by sputtering a target made of Al and Co.

The apparatus for forming the magnetic recording medium of this embodiment is an MDP1100 machine manufactured by Varian, USA, which is an in-line sputtering apparatus having a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber capable of performing a plurality of magnetron sputterings. . Not limited to this apparatus, any apparatus may be used as long as it can perform substrate temperature control and sputtering. Alloy layer 1
02. It is desirable that the pressure is maintained at 2.0 × 10 −5 Pa or less during each process of forming the protrusion 103 made of an intermetallic compound in order to prevent oxidation.

A method for forming the protrusion 103 made of an intermetallic compound will be described below in detail with reference to Table 1 and FIG.

[0040]

[Table 1] FIG. 6 is a part of an Al-Co equilibrium diagram having an intermetallic compound phase. For example, point D in FIG. 6 indicates that when the concentration of Co atoms is 14.6 atomic%, at a temperature of 500 K, the solid solution phase α of Al and the phase of the intermetallic compound Al9Co2 exist at a ratio of about 1: 4 in terms of energy. It shows that it is stable. Therefore, if the concentration of Co atoms is 14.6 atomic% and the temperature is kept at 500 K for a long enough time to sufficiently diffuse, phase α and phase θ will be formed in a ratio of 1: 4, and even if the composition is 18.2 atomic%. Temperature 500
With K, a phase of only Al9Co2 can be obtained.

Therefore, on the alloy layer 102, Al-14.6 atomic% Co
By sputtering a target consisting of Al
And protrusions 103 made of an intermetallic compound of Co and Co.
This target is obtained by uniformly mixing and sintering fine powders of Al and Co, and contains an intermetallic compound mainly composed of Al9Co2 and Al and Co uniformly mixed. Target Co
Is 14.6 atomic%, when each atom is sputtered and reaches the substrate 101 and diffuses the surface of the substrate 101 to reach an equilibrium state, the ratio of the intermetallic compound Al9Co2 is 80%.
%, And the remainder is Al (FIG. 6). In an actual process, it changes depending on process conditions such as a substrate temperature and a forming time. The material of the target is not limited to Al-14.6 at% Co, as long as it produces a phase of an intermetallic compound in an equilibrium state. The process gas used for sputtering is argon, but any inert gas that does not substantially react with the target material may be used.

As described above, the alloy layer 102, Al and Co
101 on which projections 103 made of an intermetallic compound are formed
Was observed with an atomic force microscope (AFM) and is shown in FIG. For observation, NV3000 type manufactured by Olympus Optical Industries, Ltd. was used. The dimension of one side of the field of view is 10 micrometers. Within this area, the projection density was 5.1 × 10 12 / m 2, and the projection height was 10 nm on average. The projection density and the projection height can be controlled by changing the process conditions as shown in Table 1. At the same target input power and sputtering time, the higher the substrate temperature, the easier the diffusion of atoms to occur, and therefore the higher the projection height. Also, in order to increase the projection density, it is necessary to increase the target input power or the sputtering time. However, if it is excessive, the diameter of the projection itself becomes large, the projections are united, and a huge projection is generated. The number is reduced and eventually becomes a substantially flat surface.

Next, a method of forming annular projections by laser processing will be described with reference to Table 2 and FIG. Al
Then, the CSS zone on the substrate 101 on which the protrusion 103 made of an intermetallic compound of Co and Co is formed is processed by a laser beam to form a discrete annular protrusion 105. The input laser power was 600 mW, which was reduced to 1/10 to 1/4 by a neutral density filter.
The laser used was a Q-switched pulse laser V70 having a wavelength of 1064 nm, manufactured by Spectra Physics Co., USA.
Processing is performed over the entire circumference of the CSS zone using a laser. In the present embodiment, the range of a radius of 17.3 to 20.5 mm from the center is CS
Used as S zone. This range can be arbitrarily set by those skilled in the art. The laser beam has substantially no effect outside the irradiated range, and the shape of the protrusion 103 made of an intermetallic compound is preserved. As a result, in the CSS zone, the protrusions 103 made of an intermetallic compound and the annular protrusions 105 formed by laser processing were mixed, and in the other region, only the protrusions 103 made of the intermetallic compound were formed. This is shown schematically in FIG. Further, the interval between the discrete annular projections 105 can be set at a constant interval independently in the circumferential direction and the radial direction of the substrate 101 by changing the feed speed of the substrate holding table and the number of rotations of the substrate. The height of the annular projection 105 can also be changed by changing the material and thickness of the alloy film 102, the frequency of the laser Q switch, and the laser power. This is shown in Table 2.

[0044]

[Table 2] The height of the annular projection 105 was optically measured by a device called MICRO XAM manufactured by Phase Shift Technology, USA, and AFM was used as necessary. The dimension of one side of the field of view is 10 micrometers. In the present embodiment, Co
After the ternary alloy of -Cr30Ta8 was formed to a thickness of 100 nm, the substrate was further washed, and then an alloy layer 106, a magnetic recording layer 107, and a protective film layer 108 were formed. The forming apparatus used in this example is an MDP250 machine manufactured by Intevac, USA. The forming apparatus is an inline sputtering apparatus having a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber capable of performing a plurality of magnetron sputterings. Note that any apparatus may be used as long as the control of the substrate temperature and the sputtering can be performed. In addition, during the processing for forming the alloy layer 106, the magnetic recording layer 107, and the protective film layer 108, 2.
It is desirable to keep the pressure under 0 × 10 −5 Pa.
Furthermore, the sliding reliability of a magnetic recording medium (projection density: 5.1 × 1012 / m2, average projection height: 10 nm) in which a lubricating film containing perfluoropolyether as a main component is formed to 3 nm on the protective film layer 108 is improved. Examined. The sliding test used a thin-film magnetic head known to those skilled in the art. The first was a CSS endurance test in the CSS zone, which was performed at a position of a radius of 19 mm on the substrate, and the second was an adhesion measurement in a data zone at a position of a radius of 30 mm on the substrate. These results are compared with the projections 10 made of an intermetallic compound.
The results are shown in Table 3 in comparison with Comparative Example 9 prepared under the same conditions except that No. 3 and the annular projection 105 were not formed.

[0045]

[Table 3] It can be seen that the magnetic recording medium of the present example is superior in sliding reliability to the case without the protrusion (Comparative Example 9).

The results of comparing the above-described embodiment with an example in which the surface shape is changed will be described below. There are eight comparative examples. There are five types (Comparative Examples 1-5) in which the height and the interval of the annular protrusion 105 are changed. Al-
Three types of protrusions 103 made of an intermetallic compound were formed by changing the Co concentration of the Co target (Comparative Examples 6-8).
They are 0,7.3 and 10.9%, respectively. Table 3 shows the conditions.
Shown along with.

The other conditions were the same as those of the above-described embodiment. With the annular projections 105 formed, the surface shape of the magnetic recording medium was observed by AFM for Comparative Examples 6, 7, and 8.
The measurement point is a point at R = 30 mm from the center of the substrate. In addition, a CSS test was performed on all comparative examples at a point of R = 19 mm, and R = 30 m
The adhesion was measured at point m. First, the surface shape of the magnetic recording medium at a radius R = 30 mm where only the protrusion 103 made of an intermetallic compound is formed will be described. When a Co concentration of 0, that is, pure Al, is used, no intermetallic compound for forming a projection can be generated, so that only a substantially flat surface can be obtained as shown in the AFM image of FIG.

Next, when the Co concentration is 7.3 atomic%, the surface A
FIG. 11 shows an FM image, and FIG. 12 shows an AFM image of the surface at 10.9 atomic%. When the Co concentration is 7.3 atomic%, there is more Al present in excess than the intermetallic compound forming the protrusion,
Although the thickness of the Al-rich layer in FIG. 4 is large and the valleys are buried in Al, the protrusions are not clear, but the protrusions themselves are formed. In the Al-Co system, the intermetallic compound Al5Co2
Therefore, it is preferable that the Co concentration is 7 atomic% or more and 29% or less. Similarly, Al-Cr, Al-Mo, Al-W, Al
In the -V system, Cr is 5-20 atomic%, Mo and V are 3-25
Atomic%, W is preferably 3-20%. Although there is a composition containing 40% or more of the phase of the intermetallic compound outside the above composition range, the above composition range is preferable because diffusion at a low temperature (600 K or less) hardly occurs. However, when only the protrusions are formed, the substrate can be kept at a high temperature exceeding 600 K in the process. In this case, the concentration of the minority atom X to be added is lower than the concentration of the minority atom X constituting the intermetallic compound.
The intended purpose can be achieved by using a target between 0.4 times and 1 time. Further, the results of the CSS test and the adhesive strength measurement will be described with reference to Table 3. CS
The results of the S test are shown by the adhesive strength after standing for 1 hour after 50,000 times of CSS. Those having a large protrusion interval have slightly larger adhesion, but a clear effect can be seen in comparison with Comparative Example 9 in which no protrusion is provided. Further, the other comparative examples have a greater effect on the adhesive strength at R = 30 mm than the comparative examples 6 and 9 having substantially no protrusion. It can be seen that the average projection height of the projection 103 made of an intermetallic compound needs to be 5 nm or more in order to reduce the adhesive force. Embodiment 2 Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 13 is a cross-sectional view showing a configuration in which a projection made of an intermetallic compound is formed on an Al alloy substrate in the magnetic recording medium of this example. First, Ni and P alloy plated outer diameter 95mm, inner diameter 25m
A disc-shaped Al alloy substrate 201 having a concentric hole at the center with a thickness of 0.8 mm and a thickness of 0.8 mm is lamp-heated in a vacuum for the purpose of degassing and improving magnetic recording characteristics. The input power at this time is controlled so that the alloy layer 203 formed later has a temperature that has a predetermined magnetic characteristic. Thereafter, an alloy layer 202 of chromium (hereinafter referred to as Cr) and titanium (hereinafter referred to as Ti) is formed on the substrate 201, and further, cobalt (hereinafter referred to as Co).
Alloy layer 203 of Cr and platinum (hereinafter referred to as Pt)
Are sequentially formed.

The alloy layer 203 has a function of magnetic recording.
The Cr and Ti alloy layer 202 is formed on the substrate 201 by the alloy layer 203.
Has the effect of forming the crystal grain size and crystal orientation of the alloy layer 203 with good controllability and good adhesion. The material used for the Cr and Ti alloy layer 202 and the Co, Cr and Pt alloy layer 203 may be any other material as long as it has the functions and effects described above. The material of the substrate 201 may be any material as long as it is non-magnetic and has no problem in flatness and strength.
Thereafter, the substrate 201 is processed in a processing chamber provided with a helium introduction mechanism for a predetermined time, and the substrate temperature is cooled to a predetermined temperature suitable for forming the protrusion 204 made of an intermetallic compound of Al and Cr. Note that this cooling step is not necessary if the substrate temperature has dropped to a predetermined temperature due to radiation, conduction, or the like during the transfer of the substrate from the processing chamber to the processing chamber. Any gas may be used as long as it has a cooling effect. On the other hand, when the temperature is too low, heating is performed again to a predetermined temperature. Subsequently, a projection 204 made of an intermetallic compound of Al and Cr is formed on the alloy layer 203 by sputtering a target made of Al-10 at% Cr. At this time, control is performed so that the formation of the protrusion 204 is suppressed by providing a shield around the outer peripheral portion of the substrate 201. FIG.
2 schematically shows the positional relationship between the sputtering target, the shield 210 and the substrate 201 in the vacuum processing chamber. The distance t between the shield 210 and the substrate 201 and the shield 21
By changing the diameter r of the opening 0, it is possible to control the change in the protrusion height and the protrusion density from the CSS zone to the data zone. The CSS zone (substrate radius R = 19 nm) and the data zone (substrate radius R = 30 nm) when the distance t between the shield 210 and the substrate 201 and the diameter r of the opening of the shield 210 are changed. Table 4 shows the protrusion height.

[0050]

[Table 4] As a result, the outer peripheral portion of the substrate 201 is formed such that the density and the average height of the projections 204 are lower than the inner peripheral portion, and the inner peripheral portion obtains a projection height and density suitable for CSS. On the other hand, at the same time, a desired flying height margin can be obtained in the data recording portion. This is shown schematically in FIG. Of course, if the position of the CSS zone changes, the placement of the shields must also be changed. In this embodiment, an in-line sputtering apparatus having a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber capable of performing a plurality of magnetron sputterings was used with an MDP1100 machine manufactured by Varian Corporation of the United States. Any device can be used. Cr and Ti
During the processes of forming the alloy layer 202, the alloy layer 203 of Co, Cr, and Pt, the protrusion 204 made of an intermetallic compound, and the protective film layer 205, a pressure of 2.0 × 10 −5 Pa or less is used to prevent oxidation. It is desirable to be held in. Further, a protective film layer 205 for protecting the alloy layer 203 and the protrusion 204 made of an intermetallic compound from mechanical or chemical contact is subsequently formed to obtain the structure shown in FIG. Table 5 shows the results of the adhesion test at a radius of R = 30 mm and the results of the CSS test at R = 19 mm in the configuration of FIG.

[0051]

[Table 5] It can be seen that there is an effect as compared with the case where the projection 204 made of an intermetallic compound is not formed. Furthermore, as a comparative example, after first forming a projection 204 made of an intermetallic compound on a glass substrate, an alloy layer 202, an alloy layer 203 of Co, Cr and Pt,
Table 5 shows an example in which the protective film layer 205 is formed. It can be seen that there is an effect as compared with the case where the projection 204 made of an intermetallic compound is not formed.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 16 is a longitudinal sectional view of a thin film configuration formed on a substrate.

FIG. 16 shows an example of the configuration of a thin film formed on an Al alloy substrate. First, outer diameter 9 plated with Ni and P alloys
A disk-shaped Al alloy substrate 1101 having a concentric hole at the center with a thickness of 5 mm, an inner diameter of 25 mm and a thickness of 0.8 mm is lamp-heated in a vacuum for the purpose of degassing. At this time, the supplied electric power is controlled so that the temperature becomes high enough not to deform the substrate. Typically 10
Set to 0-250 ° C. After that, silicon oxide (SiOx,
x ≦ 2) is formed by sputtering. The thickness of the SiOx thin film 1102 is 10, 50, 200 and 800.
Four types of nm were created. The thicker the film thickness is, the more the direction of heat conduction is suppressed. Subsequently, an alloy layer 1103 made of cobalt (hereinafter referred to as Co), chromium (hereinafter referred to as Cr), and tantalum (hereinafter referred to as Ta) is formed on the substrate 1101. The composition ratios of Cr and Ta are 30 atomic% and 8 atomic%, respectively, and the composition is substantially non-magnetic. In addition, four kinds of film thicknesses of the alloy layer 1103 were prepared: 25, 50, 100 and 200 nm. The smaller the film thickness, the smaller the heat capacity of the entire film, and processing is performed with a small laser power. Further, Cr and silicon (Si
Alloy), an alloy of Cr and titanium (described as Ti), C
Alloy of r and vanadium (denoted as V), nickel (denoted as Ni)
Alloys of Ti and Ti, alloys of Ni and Al, and ternary alloys of Co, Cr and zirconium (referred to as Zr) were studied. This is because the physical properties such as the absorption efficiency from the laser and the thermal conductivity differ depending on each material. Process conditions that can be set in both the thin film formation process and the laser processing process often have restrictions from the manufacturing facility side, and it is advantageous to study various process parameters in actual manufacturing.

The alloy layer 1103 on the thin film 1102 has a function of forming protrusions by irradiation with a pulse laser. The material used for the alloy layer 1103 may be any other material as long as it has the functions and effects described above. In addition, substrate 1
The substrate 101 is made of a substrate manufactured by Toyo Kohan Co., Ltd., but any material may be used as long as it is nonmagnetic and has no problem in flatness and strength.

The apparatus having the configuration shown in FIG. 16 is an MDP1100 machine manufactured by Varian, USA, which is an in-line sputtering apparatus having a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber capable of performing a plurality of magnetron sputterings. Any device can be used as long as control and sputtering can be performed. Further, it is desirable to maintain the pressure of 2.0 × 10 −5 Pa or less during the processing for forming each of the layers 1102 and 1103 in order to prevent oxidation.

Next, a method for obtaining an annular projection by laser processing will be described with reference to FIG. The substrate 1
A desired portion 101 is processed by a laser beam to form discrete annular projections 1104. The input laser power was 600 mW, which was reduced to 1/10 to 1/4 by a neutral density filter. The laser used was a Q-switched pulsed laser V80 with a wavelength of 1064 nm, manufactured by Spectra Physics, USA. Using the laser, the CSS zone of the substrate is processed over the entire circumference. In this embodiment, the radius from the center
The range is from 18.0 to 20.7 mm, and this range can be arbitrarily set by those skilled in the art. The laser beam has substantially no effect outside the irradiated area. Further, the distance between the discrete annular projections 1104 can be set at constant intervals independently in the circumferential direction and the radial direction of the substrate by changing the feeding speed of the substrate holder and the number of rotations of the substrate. The thickness can also be changed by changing the thickness of SiOx, the material and thickness of the alloy film 1103, the frequency of the laser Q switch, and the laser power. This is shown in Table 6.

[0057]

[Table 6] Table 6 compares the case where no SiOx film is formed with a film thickness of 0. The annular projection 11 with less laser power than when not formed by forming the SiOx film
04 can be formed. Annular projection 1104
Is the height of MI manufactured by Phase Shift Technology of the United States.
Optically measured with a device called CRO XAM. In this apparatus, the protrusions having a protrusion height of less than about 5 nm cannot be measured with high accuracy. The method of forming the SiOx thin film 1102 may be another method such as a chemical vapor deposition (CVD) method. The thin film 102 is not limited to SiOx but may be any material as long as it has a lower thermal conductivity than the alloy layer 1103.

Thereafter, the substrate 1101 is processed for a predetermined time in a processing chamber provided with a helium introduction mechanism, and the substrate temperature is set to Al and
Cooling to a predetermined temperature suitable for forming the protrusion 1105 of the intermetallic compound of Co. This is not necessary if the substrate temperature has dropped to a predetermined temperature due to radiation, conduction, or the like during the transfer of the substrate from the processing chamber to the processing chamber. Any gas may be used as long as it has a cooling effect. On the other hand, when the temperature is too low, heating is performed again to a predetermined temperature.

Subsequently, the alloy layer 1103 that has been subjected to the laser processing
The protrusion 1105 of the intermetallic compound of Al and Co is
The target is formed by sputtering. Table 7 shows a method for forming the protrusion 1105.
8, and will be described with reference to FIGS. The process of forming the protrusions is as described above with reference to FIGS.

[0060]

[Table 7]

[0061]

[Table 8] Here, when the excess Al atoms are so small that a crystal lattice cannot be formed, even if they are diffused, they are very small in quantity, and in any case, they do not substantially react with the adjacent alloy layer 1103. However, in the case of an atom of an alkali metal, an alkaline earth metal or a halogen element, the reactivity is so high that it cannot be used as a projection material and is not used in the invention.

FIG. 18 shows the configuration of the data zone on the substrate 1101 on which the fine projections 1105 have been formed as described above.

In this embodiment, the SiOx thin film was formed to 800 nm, and the ternary alloy of the alloy film Co-Cr30Ta8 was formed to 100 nm. Further, after forming protrusions by laser processing and forming protrusions of the intermetallic compound, the base film was formed. 1106, Magnetic recording layer 1
107 and a protective film layer 1108 were formed. A schematic diagram of this is shown in FIG. For the base film 1106, a Cr film was formed to a thickness of 25 nm by sputtering a Cr target. The process gas is Ar. The magnetic recording layer 1107 has
A Co alloy containing Cr, Ta and Pt was used. The forming method was by sputtering using Ar. The thickness is 20 nm. Regarding the protective film layer 1108, a carbon film was formed by sputtering a graphite carbon target. The process gas is Ar. The film thickness is 18 nm.
The apparatus having the configuration shown in FIG.
This is an in-line sputtering system that has a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber that can perform multiple magnetron sputtering with a P250 machine. However, any apparatus can be used as long as it can perform substrate temperature control and thin film formation processing. . Further, it is desirable that the pressure is maintained at 2.0 × 10 −5 Pa or less during the processing for forming the layers 1106, 1107 and 1108 in order to prevent oxidation. The material, thickness, and manufacturing method of the underlayer 1106 and the magnetic recording layer 1107 are not limited to the above, as long as desired magnetic recording characteristics can be obtained. The material, film thickness, and manufacturing method are not limited to the above, as long as the desired sliding reliability can be obtained for the protective film layer 1108. Further, the configuration of FIG. 19 (the density of the annular projections 104: 1.1 × 1010 / m2, the average projection height: 15 nm,
The sliding reliability was examined using a configuration in which a 3 nm lubricating film containing perfluoropolyether as a main component was formed on the fine projections 1105 (density: 5.4 × 10 12 / m 2, average projection height: 10 nm). The sliding test used an MR head known to those skilled in the art. The first was a CSS endurance test in the CSS zone, which was performed at a position with a radius of 19 mm on the substrate, and the second was an adhesion measurement in a data zone at a position with a radius of 30 mm on the substrate. These results are shown in Table 2 in comparison with a case where the laser power was adjusted so as to have the same protrusion height without forming the SiOx thin film 102. It can be seen that the sliding reliability of the magnetic disk having the SiOx thin film 1102 shown in this embodiment is almost the same as the case without the SiOx thin film 1102.

Embodiment 4 Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 20 shows an example of the configuration of a thin film formed on an Al alloy substrate. First, outer diameter 6 plated with alloy of Ni and P
A disk-shaped Al alloy substrate 1201 having a concentric hole at the center with a thickness of 5 mm, an inner diameter of 20 mm, and a thickness of 0.8 mm is heated by a lamp in a vacuum for the purpose of degassing. At this time, the supplied electric power is controlled so that the temperature becomes high enough not to deform the substrate. Typically 10
Set to 0-250 ° C. Thereafter, the substrate 1201 is processed for a predetermined time in a processing chamber provided with a helium introduction mechanism, and the substrate temperature is cooled to a predetermined temperature suitable for forming the projection 1202 of an intermetallic compound of Al and Cr. This is not necessary if the substrate temperature has dropped to a predetermined temperature due to radiation, conduction, or the like during the transfer of the substrate from the processing chamber to the processing chamber. Any gas may be used as long as it has a cooling effect. On the other hand, when the temperature is too low, heating is performed again to a predetermined temperature.

Subsequently, projections 1202 of an intermetallic compound of Al and Cr are formed on the substrate 1201 by sputtering a target made of Al and Cr. After that, silicon nitride (SiN
(x, x ≦ 1.33) A thin film 1203 is formed by reactive sputtering containing nitrogen in a sputtering gas. Said
Three thicknesses of the SiN thin film 203 were prepared: 10, 100 and 800 nm. The thicker the film thickness is, the more the direction of heat conduction is suppressed. Subsequently, Co, C is deposited on the substrate 1201 as in the first embodiment.
An r and Ta alloy layer 204 is formed. The composition ratios of Cr and Ta are 30 atomic% and 8 atomic%, respectively, and the composition is substantially non-magnetic. In addition, four types of the alloy layers 1204 having a thickness of 25, 50, 100 and 200 nm were prepared. The smaller the film thickness, the smaller the heat capacity of the entire film, and processing is performed with a small laser power. Further, as a material constituting the alloy layer, an alloy of Ni and Ti and a ternary alloy of Co, Cr and Zr were examined.

The apparatus having the configuration shown in FIG. 20 is an MDP1100 machine manufactured by Varian, USA, which is an in-line sputtering apparatus having a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber capable of performing a plurality of magnetron sputterings. Any device can be used as long as control and sputtering can be performed. In addition, during each process of forming each of the layers 1202, 203 and 1204, 2.0 × 10 −5 Pa
It is desirable to be kept under the following pressure.

The alloy layer 1204 on the substrate 1201 has a function of forming a projection by irradiation with a pulse laser. The material used for the alloy layer 1204 may be another material as long as it has the functions and effects described above. In addition, substrate 1
The substrate 201 is made of a substrate manufactured by Toyo Kohan Co., Ltd., but any material may be used as long as it is nonmagnetic and has no problem in flatness and strength.

Next, a method for obtaining an annular projection by laser processing will be described with reference to FIG. The substrate 2
A desired portion of the laser beam 01 is processed by a laser beam to form discrete annular projections 1205. The input laser power was 600 mW, which was reduced to 1/10 to 1/4 by a neutral density filter.
The laser used was a Q-switched pulsed laser V80 with a wavelength of 1064 nm, manufactured by Spectra Physics, USA.
Using the laser, the CSS zone of the substrate is processed over the entire circumference. In this embodiment, the radius is 13.5 from the center.
To 15.1 mm, but this range can be arbitrarily set by those skilled in the art. The laser beam has substantially no effect outside the irradiated area. Further, the interval between the discrete annular projections 1205 can be set independently at a constant interval in the circumferential direction and the radial direction of the substrate by changing the feeding speed of the substrate holding table and the number of rotations of the substrate. The thickness can also be changed by changing the thickness of SiN, the material and thickness of the alloy film 1204, the frequency of the laser Q switch, and the laser power. This is shown in Table 7.
Table 7 shows a comparison in the case where the SiNx film is not formed as a film thickness of 0. By forming the SiNx film, the annular projection 12 can be formed with less laser power than when not formed.
05 can be formed. Annular projection 1205
Is the height of MI manufactured by Phase Shift Technology of the United States.
Optically measured with a device called CRO XAM. In the apparatus, the projections having a projection height of less than about 5 nm cannot be measured with high accuracy. It can be seen that the annular projection 1205 can be formed with a smaller laser power than when no SiNx film is formed. The method of forming the SiNx thin film 1203 may be another method such as chemical vapor deposition (CVD). The thin film 1203 is not limited to SiNx and may be any material as long as it has a lower thermal conductivity than the alloy layer 1204.

Further, by laminating the magnetic recording layer and the protective layer on the substrate having the structure shown in FIG. 21, a magnetic disk excellent in sliding property can be easily obtained.

The method for forming the projections 1202 is the same as that of the third embodiment. The target used in Example 4 is Al-7.6 atomic% Cr, and the target is Al
It is obtained by uniformly mixing and sintering fine powders of Cr and Cr, and the intermetallic compound mainly composed of Al7Cr and Al and Cr are uniformly mixed.

In this embodiment, a base film 1206, a magnetic recording layer 1207, and a protective film layer 1208 are formed on the ternary alloy of the alloy film Co-Cr30Ta8 having a thickness of 100 nm, and after washing the substrate. This schematic diagram is shown in FIG. As for the base film 1206, a CrTi film was formed to a thickness of 25 nm by sputtering a CrTi20 target. The process gas is Ar. The magnetic recording layer 1207 contains Co containing Cr and Pt.
An alloy was used. The forming method was by sputtering using Ar. The film thickness is 22 nm. Regarding the protective film layer 1208, a carbon film containing nitrogen was formed in the structure using reactive sputtering. The process gas is Ar-20% N2 and the target is graphite carbon. The thickness is 15 nm. The apparatus having the configuration shown in FIG. 22 is an MDP250 machine manufactured by Intevac Corporation in the United States, which is an in-line sputtering apparatus having a substrate heating chamber, a substrate cooling chamber, and a substrate processing chamber capable of performing a plurality of magnetron sputterings. Any device can be used as long as sputtering can be performed. It is desirable that the pressure is maintained at 2.0 × 10 −5 Pa or less during the processing for forming the layers 1206, 1207 and 1208 in order to prevent oxidation. Base film 1206
The material, thickness, and manufacturing method of the magnetic recording layer 1207 are not limited to those described above as long as desired magnetic recording characteristics can be obtained. The material, film thickness, and manufacturing method are not limited to the above, as long as the desired sliding reliability can be obtained for the protective film layer 1208 as well. Further, the configuration of FIG. 22 (the density of the annular projections 1104: 1.1 × 1010 / m2, the average projection height:
The sliding reliability was examined in a configuration in which a 3 nm lubricating film containing perfluoropolyether as a main component was formed on 15 nm, the density of fine projections: 5.5 × 10 12 / m 2, and the average projection height: 11 nm. The sliding test used an MR head known to those skilled in the art. The first was a CSS endurance test in the CSS zone, which was performed at a 14.3 mm radius of the substrate, and the second was an adhesion measurement in the data zone at a 22 mm radius of the substrate. These results are shown in Table 9 in comparison with a case where the SiNx thin film 1203 was not formed and other specifications were made under substantially the same conditions.

[0073]

[Table 9] Table 9 shows the presence or absence of the SiNx film, the height of the protrusion, and the sliding test results. It can be seen that the sliding reliability of the magnetic disk having the SiNx thin film shown in the present example is almost the same as that without the SiNx thin film.

[0074]

According to the present invention, it is possible to obtain a magnetic recording medium which is hard to stick to the head and has excellent sliding resistance, and can provide a magnetic disk drive having excellent sliding reliability.

The present invention also provides a method of manufacturing a magnetic recording medium that enables laser processing on a metal substrate with a small laser power. For this reason, a magnetic disk excellent in sliding resistance, which is less likely to stick to the head, can be obtained with a simpler device, and a magnetic disk device excellent in sliding reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a state diagram illustrating a process of forming fine protrusions made of an intermetallic compound.

FIG. 2 is a diagram illustrating a process of forming fine protrusions made of an intermetallic compound.

FIG. 3 is a diagram illustrating a process of forming fine protrusions made of an intermetallic compound.

FIG. 4 is a diagram illustrating a process of forming fine protrusions made of an intermetallic compound.

FIG. 5 is a view showing Example 1 of the present invention in which fine projections made of an intermetallic compound are formed.

FIG. 6 is an Al-Co phase diagram for explaining a process of forming fine projections made of an intermetallic compound.

FIG. 7 is a photograph showing an AFM image when a projection is formed using an Al-14.6% Co target.

FIG. 8 is a cross-sectional view of the magnetic recording medium that is Embodiment 1 of the present invention.

FIG. 9 is a schematic diagram illustrating a magnetic recording medium that is Embodiment 1 of the present invention.

FIG. 10 is a photograph showing an AFM image of the surface of a magnetic recording medium as a comparative example.

FIG. 11 is a photograph showing an AFM image when protrusions are formed using an Al-7.3% Co target.

FIG. 12 is a photograph showing an AFM image when protrusions are formed using an Al-10.9% Co target.

FIG. 13 is a view showing Example 2 of the present invention in which fine projections made of an intermetallic compound are formed.

FIG. 14 is a schematic diagram illustrating a magnetic recording medium that is Embodiment 2 of the present invention.

FIG. 15 is a schematic view showing equipment for forming fine projections.

FIG. 16 is an example of a cross section of a layer configuration for forming an annular projection by laser processing.

FIG. 17 is an example of a cross section of a configuration of an annular projection formed by the method of the present invention.

FIG. 18 is an example of a cross section of a fine projection on a data zone formed by the method of the present invention.

FIG. 19 is a schematic diagram showing an example of a magnetic disk constructed by the method of the present invention.

FIG. 20 is an example of a cross section of a fine projection on a data zone formed by the method of the present invention.

FIG. 21 is an example of a cross section of an annular protrusion on a CSS zone formed by the method of the present invention.

FIG. 22 is a schematic diagram showing an example of a magnetic disk constructed by the method of the present invention.

[Explanation of symbols]

101: substrate, 102: base alloy layer, 103: fine projection, 104: annular projection, 107: magnetic recording layer, 108
... Protective film layer.

Continued on the front page (72) Inventor Akira Ishikawa 2880 Kozu, Odawara-shi, Kanagawa Prefecture Storage System Division, Hitachi, Ltd.

Claims (21)

[Claims] 1. A non-magnetic substrate, a projection made of an intermetallic compound formed on the substrate, a magnetic recording film formed on the substrate having the projection made of the intermetallic compound, and the magnetic recording And a protection film formed on the film, wherein at least a part of the surface of the base has protrusions of substantially constant height formed at substantially constant intervals different from the protrusions made of the intermetallic compound. A magnetic recording medium characterized by the above-mentioned. 2. A non-magnetic substrate, a magnetic recording film formed on the substrate, a protrusion made of an intermetallic compound formed on the magnetic recording film, and a protrusion formed on the protrusion and the magnetic recording film. And a projection having a substantially constant height formed at a substantially constant interval different from the projection made of the intermetallic compound in at least a part of the surface of the magnetic recording film. Characteristic magnetic recording medium. 3. A base made of glass, a non-magnetic metal thin film formed on the base, a protrusion made of an intermetallic compound formed on the metal thin film, and a protrusion made of the intermetallic compound A magnetic recording film formed on the metal thin film having: a protective film formed on the magnetic recording film; and a projection made of the intermetallic compound on at least a partial region of the surface of the metal thin film. A magnetic recording medium having projections of substantially constant height formed at different substantially constant intervals. 4. The method according to claim 1, wherein the projection made of the intermetallic compound is composed of atoms of aluminum and atoms of one element selected from chromium, cobalt, molybdenum, vanadium and tungsten. 4. The magnetic recording medium according to any one of claims 1 to 3. 5. The magnetic recording according to claim 3, wherein a thin film made of a material having low thermal conductivity is formed on the substrate, and the nonmagnetic metal thin film is formed on the thin film. Medium. 6. The magnetic recording medium according to claim 5, wherein said thin film made of a material having low thermal conductivity is made of silicon oxide or nitride. 7. A non-magnetic substrate, a thin film made of a material having a low thermal conductivity, a non-magnetic metal thin film, and a laser beam irradiating a desired portion to control a height formed in a regular manner. A magnetic recording medium comprising: a plurality of protrusions arranged in a matrix; a fine structure film having fine protrusions on a surface mainly composed of an intermetallic compound; a magnetic recording film; and a protective film. 8. A non-magnetic substrate, a thin film made of silicon oxide or nitride, an alloy of cobalt, chromium and tantalum, an alloy of chromium and silicon, an alloy of chromium and titanium, an alloy of chromium and vanadium, nickel A non-magnetic metal thin film made of an alloy selected from the group consisting of an alloy of titanium, an alloy of nickel and aluminum, and an alloy of cobalt, chromium, and zirconium; Magnetic recording characterized by comprising regularly arranged protrusions with controlled thickness, a fine structure film having fine protrusions on the surface mainly composed of an intermetallic compound, a magnetic recording film, and a protective film. Medium. 9. The magnetic recording medium according to claim 6, wherein said non-magnetic metal thin film has a thickness of 200 nm or less. 10. An average density of projections made of the intermetallic compound is 1.0 × 10 12 / m 2 or more, and a height (a distance from a flat portion to a vertex in a vertical direction with respect to the substrate) is 5 nm or more on average. The projections different from the projections made of an intermetallic compound at the same time have an average density of 1.0 × 10 8 / m 2 or more and a projection height of 10 nm or more on average.
The magnetic recording medium according to the above. 11. The density of protrusions on the surface of the magnetic recording medium is at least 1.0 × 10 12 / m 2 on the surface of the magnetic recording medium on which contact start / stop is planned, and the protrusion height (The distance from the flat portion to the top in the vertical direction with respect to the substrate) is 15 nm or more on average,
The magnetic recording medium according to any one of claims 1 to 9, wherein the density is 1.0 x 1012 particles / m2 or more on average on a surface where no start / stop is planned, and the projection height is 5 nm or more on average. 12. A substrate having a nonmagnetic substrate and a projection made of an intermetallic compound formed on the substrate, wherein at least a part of the surface of the substrate is different from the projection made of the intermetallic compound. A magnetic recording medium substrate having projections formed at a constant interval and having a substantially constant height. 13. A metal substrate comprising: a base made of glass; a nonmagnetic metal thin film formed on the base; and a projection made of an intermetallic compound formed on the metal thin film. A substrate for a magnetic recording medium, comprising a projection having a substantially constant height formed at a substantially constant interval different from the projection made of the intermetallic compound in at least a part of the surface. 14. The magnetic recording according to claim 12, wherein a thin film made of a material having a low thermal conductivity is formed on the substrate, and the nonmagnetic metal thin film is formed on the thin film. Substrate for media. 15. The substrate for a magnetic recording medium according to claim 14, wherein said thin film made of a material having a low thermal conductivity is made of silicon oxide or nitride. 16. A non-magnetic substrate, a thin film made of a material having a low thermal conductivity, a non-magnetic metal thin film, and a laser beam irradiated to a desired portion to control a height formed in a regular manner. A magnetic recording medium substrate having projections arranged on the substrate. 17. A non-magnetic substrate, a thin film of silicon oxide or nitride, an alloy of cobalt, chromium and tantalum, an alloy of chromium and silicon, an alloy of chromium and titanium, an alloy of chromium and vanadium, nickel A non-magnetic metal thin film made of an alloy selected from the group consisting of an alloy of titanium, an alloy of nickel and aluminum, and an alloy of cobalt, chromium, and zirconium; A magnetic recording medium substrate having projections which are controlled and regularly arranged. 18. A fine projection is formed by sputtering a target mainly containing an intermetallic compound on a nonmagnetic substrate, and the projection is formed on at least a part of the surface of the substrate on which the fine projection is formed. Irradiating a laser beam to form projections having a substantially constant height at substantially constant intervals, further forming a magnetic recording film on the base, and forming a protective film on the magnetic recording film. A method for manufacturing a magnetic recording medium. 19. A non-magnetic metal thin film is formed on a substrate made of glass, and fine projections are formed on said metal thin film by sputtering a target containing an intermetallic compound as a main component. A thin film and at least a partial area of the surface of the substrate on which the fine projections are formed are irradiated with a laser beam to form projections having a substantially constant height at substantially constant intervals, and a magnetic recording film is formed on the substrate. Forming a protective film on the magnetic recording film. 20. A step of forming a thin film made of a material having low thermal conductivity on a non-magnetic substrate, a step of forming a non-magnetic metal thin film, and irradiating a desired portion of the substrate with a laser beam. A step of forming regularly arranged protrusions whose height is controlled; a step of forming a microstructure film having fine protrusions on the surface by sputtering a target mainly composed of an intermetallic compound; A method for manufacturing a magnetic recording medium, comprising: a step of forming a film; and a step of forming a protective film. 21. The method according to claim 20, wherein the thin film made of a material having a low thermal conductivity is made of silicon oxide or nitride.